In a liquid crystal display device, a liquid crystal is a substance that does not itself illuminate light. Instead, the liquid crystal relies on light received from a light source, thereby displaying images and data. In the case of a typical liquid crystal display, a backlight system powered by electricity supplies the needed light.
Typically, the bottom-lighting type backlight system includes a plurality of light sources, a number of optical sheets, and a frame fixing the light sources and accommodating the optical sheets. The optical sheets can be selected from a group consisting of a diffusing plate, a prism sheet, or a brightness enhancement film. The optical sheets are used to improve the backlight system's optical uniformity.
Referring to FIGS. 10 through 12, a typical frame 10 for use in bottom-lighting type backlight system with an optical sheet 16 is shown. The frame 10 includes a metal main frame 12 and a receiving frame 14. The main frame 12 is a rectangular housing, which includes a base 122 and a circumferential sidewall 124 extending from the base 122 to define an opening (not labeled). The main frame 12 is usually manufactured by being punched out from a metal sheet. A plurality of positioning pins 126 is disposed on the top the sidewalls 124. The receiving frame 14 has a frame body (not labeled) defining a rectangular opening (not labeled) therein, and a plurality of pinholes 146 disposed on the frame body corresponding to the positioning pins 124. The receiving frame 14 can be mounted onto the top of the main frame 12 by inserting the positioning pins 124 in the corresponding pinholes 146, so that the lengths of the frame body should be configured to match with that of the main frame 12.
In order to accommodate the optical sheet 16, widths of two opposite frame body of the receiving frame 14 is configured to be larger than that of the corresponding sidewalls 124 of the main frame 12. The optical sheet 16 also defines a plurality of pinholes 166 thereon corresponding to the positioning pins 126, thus, the optical sheets 16 can be fixed onto the receiving frame by inserting the positioning pins 126 through the corresponding pinholes 146 and 166.
However, the process of assembling the frame 10 and fixing the optical sheet 16 on the receiving frame 14 is complicated, because it is needed to respectively insert the positioning pins 126 through the pinholes 146 of the receiving frame 14, and also through the pinholes 166 of the optical frame 16. In addition, in order to configure a plurality of positioning pins 126 or pinholes 146 on the top of the sidewalls 124 of the main frame 12 and the receiving frame 14, the main frame 12 and the receiving frame 14 requires more setup space, thus, widths of sidewalls 124 of the main frame 12 and the receiving frame 14 is large.
What is needed, therefore, is a frame, and backlight system using the same that has a narrow-framed, space-saving design, such that it can be assembled easily.